The production quality, as with all Super Genius Games products is very high, and unlike many other pdf publishers, the product is in a screen friendly format that I wish was more common, especially among pdf only publishers. It is less practical for printing out, but I can't remember the last time I printed more than the relevant sections of such a product. There is however one glaring mistake – several feats are not listed in the summary table!
Sadly the name is much more impressive than the actual product in a way; the feats are certainly powerful, but most are not horrifically overpowered, and many could be used in a campaign without any change. That makes the product more useable, but it's not the April Fool's day product I was hoping for. And since the feats vary so much in power, you have to be careful what feats you allow under what conditions.
In the end this product amused me and gave me some interesting ideas, so I will give it four stars.
So let me close with my opinion on the various feats. I'll also group them into three categories.
Not overpowered: The feat could be used as is. It might be a bit more powerful than your average feat, but many characters would pass it on for more useful feats.
Overpowered: Powerful feats, but useful only in limited situations. Feats in this category usually are close to but more powerful than existing feats or have some serious limitation.
Horrifically overpowered: That's what you'd expect in this book. Introduction into a campaign will have serious consequences and will change how things play out. That said, if you have a new player in the game (or a serious role player who build the character and his items for story telling purpose) who build a significantly less powerful character, these feats may offer you an inspiration for a reward you could give the player to bring him more in line with the rest of the party.

Feats:
Denied – not overpowered – once per day you are not affected by an attack. This is basically an automatic improved evasion against any form of attack, but just once per day. Useful, cinematic if desired, but not overpowered.
Eschew Foci – not overpowered – cast spells without the focus. How many spells require a focus other than a holy symbol? Not many, and by the time you get those spells, the foci are a token expense. The only place I can see this feat as useful is if the cleric is somehow separated from his holy symbol, either because they were taken prisoner or because they're infiltrating a cult.
Eschew Gestures/Incantations – overpowered – these two feats are the combination of three epic level feats in 3.0, and while they don't boost spell effects, they make it very easy to hide spell casting. The feats are especially overpowered in city/court campaigns.
Extra Lives –overpowered – the first three times you die, you miraculously survive. If you are DMing an AP, it might be a good idea to give every PC this feat, so the first few times they mess up they can continue without needing new characters. If you do so, make sure not to pull any punches and play the enemy as intelligent as they should be. Even a TPK or two won't end the campaign, but will add to the drama instead. And think about what giving this feat as bonus feat will tell the players about your campaign.
Favored – not overpowered – each HD gives a favored class bonus from any class in addition to any bonus you would normally get. The normal bonus equals the Toughness feat or an additional skill point per level. The APG options are a bit more diverse, but not massively more powerful.
(Regular/Greater/Ultimate) Full Casting Action – overpowered – cast an additional spell per round at -5 caster level. Not quite as horrifically overpowered as the first glance suggests, but still very powerful. Of course spellcasters burn their spells very quickly if they use this option, so if your party has long adventuring days, these feats may actually not be overpowered. This should be limited to player who know what they do, or the spellcasters turn may take a very long time - especially since durations and level dependent effects may be different for the same spell because of when it ws cast.
Gestalt – horrifically overpowered – despite the name, this does not make you a full gestalt character. You don't get spell casting, skills, BAB, HD, or saving throws at all; instead you just get the class features up to half your HD. This means that the actual power of the feat varies a lot. Even if you allow other overpowered feats, I would suggest against this feat, because it makes the character a lot more complex and unless the player is an expert on both classes, he will take noteworthy longer during his combat turn.
Go first – not overpowered – you automatically win initiative. With improved initiative a prerequisite, this means you've spend two feats to ensure you go first. You should go first.
Healing Factor – not overpowered – Fast healing HD/3. It sounds powerful, but is marginally useful in combat. The most significant effect on combat is that it negates hp bleed damage, which is very rare to begin with. The party saves a bit of money on between encounter healing, but wands of cure light are easily affordable even for lower level parties. It's the upper end of normal feats, but not quite overpowered yet.
Heroic grace – horrifically overpowered – add a mental stat bonus to saves. It's effectively a more general version of the paladin's class feature and basically allows any caster to add their casting stat to saves.
Hex Maven – overpowered – witch hexes that are limited to once/day/target can be used a number of times equal to Int modifier. I'm not sure how often this would come up; I think it may turn out that this is most useful for healing party members.
Magic User – horrifically overpowered – as Gestalt, but granting magic instead of class features. Only it will probably slow down the game even more than Gestalt.
Master of Magic Items –overpowered – you can use all magic items. In higher levels you can usually pass the UMD skill check easy enough and in low levels there are few items this is useful for. I'd judge it not overpowered, except that it is more powerful than any other feat related to UMD. However unless you specialized in using items you don't qualify for, you'll probably have more useful feats to choose from.
(Mental/Physical) Paragon – horrifically overpowered - all (mental/physical) attributes count as if you rolled 18. Until you've run a campaign with high attribute scores, it's easy to underestimate just how powerful they are.
Offensive Combat Training –overpowered – gain good BAB progression. The slow BAB classes only need to make ranged touch attacks, and the bonus for other classes is limited. It's more powerful than a normal feat, but doesn't quite reach horrifically overpowered levels.
Prestigious – horrifically overpowered – as Gestalt, just with a prestige class.
Skill Domination – overpowered – all skills are class skills and can be used untrained. Given the way skills work in Pathfinder, without ranks the character will fail most skill checks, and if you spends skill points in so many skills, you will have few (if any) high rank skills. Technically far more powerful than any feat dealing with skills, it has limited practical use.
Skill God – overpowered – for one skill, you effectively roll 20 on all checks. Very useful, but the effective difference to feats like skill focus is not that great. You still need to spend skill points to ensure success.
Spell Shifting – horrifically overpowered – Chose one spell/HD as default spell, like healing for clerics. Spontaneous casters instead can use it 1/day, but still use up a spell slot of the correct level. Lots of extra spells for spontaneous casters, lots of spells to cast without memorizing them for preparing casters; you're basically guaranteed to have the correct spells available.
Supernatural Spell Monster –overpowered – select one spellcasting class and cast all spells as if they were supernatural abilities. Obviously this gets rid of AOO's. Powerful, but situational.
Unflappable – not overpowered – never surprised, never flat footed. The character can always act in surprise rounds and will always retain the Dex bonus to AC, but he can still be flanked and sneak attacked.

Meta Attacks – changes to regular attacks usable a limited number of times a day. You must always choose to use them before making the attack role; if you miss the daily use is wasted. Every Meta Attack is an attack action, not a standard action, so it can be used with iterative attacks. Activating a Meta Attack is a swift action, so you can do just one per round, unless you spend your move action to activate a second Meta Attack.
Empowered Attack – not overpowered – +50% damage if the attack hits, twice per day. Unless you role a critical hit after you chose to use this feat, the benefits are in line with other combat feats.
Enlarge Attack – not overpowered – either throw melee weapon without penalty or double range increment of a weapon, 3/day. How often do range increments matter? How often are you willing to throw your melee weapon? Yeah, me too.
Extended Attack – overpowered – target suffers bleed damage equal to the actual hit at beginning of the next round, 3/day. It's the number of times this feat can be used per day that makes it overpowered; 1/day would be in line with existing feats.
Extra Meta Attacks – horribly overpowered – get 2 plus number of Meta Attack feats in extra uses of Meta Attacks. It's overpowered because the other attack feats are mostly balanced by their number of uses per day, and this feat messes that system of balance up totally.
Heighten Attack – not overpowered – ignore DR/Hardness equal to BAB, 4/day. Useful, but far weaker than class features like smite that penetrate all DR and do more beside.
Maximize Attack – underpowered – attack deals maximum damage, 1/day. Yep, underpowered. This feat affects only the dice role – once per day, if you hit. I would say 3/day uses would make it competitive with other feats.
Perfect Blow – not overpowered – treat as natural 20 on attack role, bypassing all protections, DR, and miss chance, 1/day. Powerful, but you still need to confirm the critical.
Quickened Attack – not overpowered – extra attack as swift action, target is flat-footed, 1/day.
Silent Attack – not overpowered – attack without breaking stealth or invisibility, 3/day. While the attack can't be traced back to you, the target is not necessarily flat-footed. It can be used to great effect, but requires good stealth to begin with.
Still Attack –not overpowered – attack without moving, even if you can't move, 3/day. Honestly this feat may be the most absurd I've ever heard off. It's obvious why it's here – the equivalent to Still Spell – but it just doesn't work for me. There's no explanation of how the damage is done, or whether your weapon would become bloody; mechanically sound, but poor flavor.
Widen Attack –overpowered – attack up to four adjacent enemies at once, 3/day. This is essentially whirlwind attack 3/day as an attack action without prerequisites. Add Spring Attack as prerequisite and either reduce to 1/day or make it a standard action to bring it in line with normal feats.